Mexico's President Enrique Pena Nieto stands with Britain's Queen Elizabeth during a state banquet at Buckingham Palace in London March 3, 2015. (Reuters/Dominic Lipinski) / Reuters

Prime Minister David Cameron will raise human rights concerns with the Mexican president Enrique Pena Nieto during his three-day state visit to the UK, Downing Street said.

There has been growing
pressure on the president over the abduction and alleged murder
of 43 students.

The Mexican president has already met Deputy Prime Minister Nick
Clegg, Home Secretary Theresa May and several dignitaries,
including the Queen and the Duke of Edinburgh during his visit.

Human rights campaigners are using the visit of Pena Nieto to
highlight what Amnesty International UK has described as
“out-of-control” torture in Mexico. Amnesty has urged
the British prime minister to discuss human rights issues in
Mexico with Pena Nieto.

The students' disappearance and alleged slaughter in Ayotzinapa
in September last year sparked weeks of protests across Mexico
against corruption and violence.

Cameron's official spokesman said: “You can expect the prime
minister to raise concerns that have arisen with regard to human
rights and the judicial system in Mexico.

“We have done so before and will continue to do that. We will
do that in the spirit of collaboration that we have with the
Mexican government and the Mexican authorities.”

“Our democracy has not been without difficulties,” he
told the House of Lords, the upper house of the British
parliament, on Tuesday. “In the recent past, we have
experienced painful moments for the acts of barbarism committed
by organized crime.”

“These criminal acts have made clear that we must continue to
strengthen the rule of law.”

Amnesty International criticized the government of former
president Felipe Calderon, which declared a “war”
against drug traffickers in 2006.

“Since Mexico launched a ‘war on drugs’ in 2006, there have
been more than 100,000 killings and over 22,000
disappearances.”

Amnesty International UK’s Stop Torture campaign manager Tom
Davies said: “While President Peña Nieto is getting the
red-carpet treatment, his police and security services have
serious blood on their hands.

“With public officials complicit in drug cartel crimes, as
well as thousands of torture cases of its own, President Peña
Nieto needs to radically overhaul his country’s woeful response
to this crisis.”

Pena Nieto was welcomed with a banquet hosted by Queen Elizabeth
II at Buckingham Palace, where he and his wife Angelica Rivera
are staying until Thursday.

Ahead of the president’s visit, around 150 Mexicans protested
outside Downing Street, calling on Cameron not to turn a blind
eye to Mexico's “human rights crisis.” Some had their
faces painted as skulls, traditionally worn during the Mexican
Day of the Dead festival. The chanting crowd counted to 43 in
memory of the missing students.

Amnesty campaigners recently delivered a 14,000-strong petition
on torture to the Mexican Embassy in central London in a bright
yellow three-meter-wide piñata. It was broken open by a person
wearing a blindfold carrying the slogan: “President Peña
Nieto: Don’t turn a blind eye to torture.”